Chain watch



FIG. 1 is a top perspective view of a chain watch;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a side elevation view thereof; and,

FIG. 4 is an enlarged sectional view of a link of the chain watch shown separately for completeness of illustration.

The broken lines shown in the drawings illustrate portions of the chain watch that form no part of the claimed design. 

CLAIM The ornamental design for a chain watch, as shown and described. 